a(n) = (A000522(2*n) + 1)/2.A086894a(n) = (A000522(2*n) + 1)/2.Terms a(0) =1a(1) =3a(2) =33a(3) =979a(4) =54801a(5) =4932051a(6) =651030673a(7) =118487582403External referencesoeis: A086894